According to INRIX, a traffic information group, Los Angeles was named as the U.S. city with the most traffic congestion. / Kevork Djansezian, Getty Images

by Larry Copeland, USA TODAY

by Larry Copeland, USA TODAY

Editor's note: A previous version of the story had an incorrect time frame for the amount of time spent in traffic.

After seven years of modest gridlock during the Great Recession, data from 2013 shows that traffic congestion is on the way back, even with only moderate job growth in some cities.

Nationwide, congestion was up 6% in 2013, with the average commuter in the nation's 10 worst traffic cities wasting an average of 47 hours a year - or more than a week's vacation - sitting in traffic; that's up from 42 hours for those cities in 2012.

That's from the annual nationwide report on congestion from congestion tracking firm INRIX.

"Traffic's coming back," says Jim Bak, INRIX's director of community relations and author of the report. "It's still not where it was before the recession. However, it is getting worse, and the question now is how do we prevent bad traffic from inhibiting our economic recovery."

In 2013, 61 of the nation's largest 100 cities had increased traffic congestion, a significant change from 2012, when only six cities saw increases, INRIX says. Congestion nationally was up for seven consecutive months from January through July last year, dropped 2.7% in August and rose September through December.

INRIX's report on increasing congestion comes on the heels of new data from the Federal Highway Administration showing that even as the nation recovers from the recession, the number of miles driven by Americans remains flat. FHWA reported in late February that total miles traveled in the USA grew by 0.6% in 2013, slower than the 0.7% population growth.

Last year was the ninth consecutive year of driving decline, says U.S. PIRG, the Federation of State Public Interest Research Groups.

The rise in congestion and simultaneous drop in driving is due partly to the fact that vehicle miles traveled for commercial trucks dipped during the recession, but not as much as for personal vehicles, says Robert Puentes, a transportation expert and senior fellow with the Brookings Institution's Metropolitan Policy Program. "We haven't seen the same dramatic decline in truck traffic (congestion) as for passenger vehicles," he says.

Mileage driven for trucks has rebounded more than for passenger vehicles, as the improving economy means more goods being traded between metropolitan areas, Puentes says. These trucks often contribute to congestion by getting gridlocked at one of the choke points that drive up congestion for a city.

iNRIX, based in Kirkland, Wash., creates its National Traffic Scorecard Annual Report from its archive of real-time traffic information for the past five years. It analyzes real-time data from a variety of sources, including road sensors and real-time traffic speeds crowd-sourced from millions of vehicles and mobile devices.

Among the 10 most congested cities, the largest increase in gridlock was in Boston, where the average total annual hours wasted in traffic increased from 31 to 38 hours, which INRIX attributes to employment growth. Washington, D.C., was the only top-10 city that saw a decrease, down from 41 to 40 hours, attributed to sequester-related cuts in government spending and hiring.